body {
    background-color: rgba(0, 0, 0, 0.899);
    overflow: scroll;
    color: white;
}


nav {
    position: relative;
    display: inline-block;
    width: 200px;
    height: 1000%;
    position: fixed;
    margin-left: -10px;
    margin-top: -20px;
    border-right-style: solid;
    border-right-width: 1px;
    border-right-color: rgb(223, 223, 223);
}

nav a {
    text-decoration: none;
}

a {
    color: rgb(255, 255, 255);
    font-size: 25px;
    text-decoration: none;
}

nav>ul>li {
    margin-top: 15px;
    margin-left: 12px;
    margin-right: 15px;
    margin-bottom: 15px;
}

nav>ul {
    list-style-type: none;
    position: relative;
    display: inline-block;
}

img.circle {
    border-radius: 50%;
    width: 100px;
    height: 100px;
    margin-left: 50px;
    margin-top: 20px;
    margin-bottom: -15px;
}

nav>div>h1 {
    color: rgb(255, 255, 255);
    font-size: 30px;
    margin-left: 40px;
    margin-bottom: 30px;
}

nav>ul::before {
    content: '';
    height: 0%;
    width: 3px;
    background-color: white;
    position: absolute;
    left: 25px;
    transition: height 0.36s;
}

nav>ul:hover::before {
    height: 100%;
}

div.article {
    position: absolute;
    display: inline-block;
    margin-top: 20px;
    margin-left: 250px;
    width: 850px;
    height: auto;
    color: rgb(255, 255, 255);
}



header {
    margin: 0px, 0px, 0px, 0px;
    padding-left: 30px;
    padding-bottom: 20px;
    border-bottom-style: solid;
    border-bottom-width: 2px;
    border-color: rgb(108, 108, 108);
}

header h1 {
    font-size: 50px;
}

article {
    margin: 0px, 0px, 0px, 0px;
    padding-left: 30px;
}

p {
    margin-top: 10px;
    font-size: 20px;
    text-indent: 2em;
    /* 首行缩进2em的距离 */
    font-family: "STZhongsong", "Microsoft Yahei", "STKaiti", "Source Han Sans CN", Verdana, Arial, Helvetica, sans-serif;
}

h3 {
    font-family: "SimSun";
    margin-top: 70px;
    margin-bottom: 10px;
    font-size: 30px;
    position: relative;
}


div.menu {
    position: absolute;
    display: inline-block;
    margin-top: -10px;
    margin-left: 1170px;
    width: 300px;
    height: 1000%;
    position: fixed;
    border-left-style:solid ;
    border-left-width: 1px;
    border-left-color: rgb(223, 223, 223);
}

div.tool{
    margin-left: 0px;
    margin-top: 30px;
}

div.tool>ul {
    list-style-type: none;
    position: relative;
    display: inline-block;
    width: 140px;
}
div.tool>ul>li {
    margin-top: 15px;
    margin-left: 6px;
    margin-right: 15px;
    margin-bottom: 15px;
}

div.tool>ul::before {
    content: '';
    height: 0%;
    width: 3px;
    background-color: white;
    position: absolute;
    right: -40px;
    transition: height 0.36s;
}

div.tool>ul:hover::before {
    height: 100%
}

#process{
    display: inline-block;
    width: auto;
    margin-left: 20px;
    margin-top: 30px;
    position: relative;
}
#process a::before {
    content: '';
    height: 3px;
    width: 0%;
    position: absolute;
    bottom: -5px;
    background-color: white;
    transition: width 0.36s;
}

#process a:hover::before {
    width: 100%;
}